By Yuzhi Li, Haifeng Zhang, Lee. Johnston and Wayne Martin 2018. Animals 2018, 8(1), 13
The objective of this study was to investigate the association between social structure and incidence of tail-biting in pigs. Pigs (n = 144, initial weight = 7.2 ± 1.57 kg, 4 weeks of age) were grouped based on their litter origin: littermates, non-littermates, and half-group of littermates. Six pens (8 pigs/pen) of each litter origin were studied for 6 weeks. Incidence of tail injury and growth performance were monitored. Behavior of pigs was video recorded for 6 h at 6 and 8 weeks of age. Video recordings were scanned at 10 min intervals to register pigs that were lying together (1) or not (0) in binary matrices. Half weight association index was used for social network construction. Social network analysis was performed using the UCINET software. Littermates had lower network density (0.119 vs. 0.174; p < 0.05), more absent social ties (20 vs. 12; p < 0.05), and fewer weak social ties (6 vs. 14, p < 0.05) than non-littermates, indicating that littermates might be less socially connected. Fifteen percent of littermates were identified as victimized pigs by tail-biting, and no victimized pigs were observed in other treatment groups. These results suggest that littermates might be less socially connected among themselves which may predispose them to development of tail-biting.
Tail docking is a well-known practice in pig production, but it is also heavily criticised. An international team of researchers dived into the topic and wondered what its exact effects are on pigs – and what alternatives there are to avoid tail biting….
Note: This article is an approved summary of the Executive Summary which was published earlier this year at http://farewelldock.eu. In future issues of Pig Progress, to be published later this year, several participating researchers in this project will delve deeper into the individual topics they encountered.
Tail docking of pigs is under scrutiny due to concerns about animal welfare. To reevaluate the consequences of raising pigs without tail docking under modern, commercial-like conditions, a study was conducted to compare welfare, behavior, and performance of pigs with and without tail docking. Pigs farrowed to 37 sows were used with half of each litter tail-docked (docked) after birth and remaining pigs left with tails intact (intact). During the nursery period, pigs (n = 336, initial wt = 7.8 ± 1.5 kg) were housed in 20 docked pens and 22 intact pens (8 pigs/pen). During the growing-finishing period, pigs (n = 240, initial wt = 24.9 ± 2.9 kg) were housed in 8 pens (4 pens each of docked and intact, 30 pigs/pen) for 16 wk (avg final wt = 126.2 ± 10.3 kg). Weight gain and feed intake were recorded. All pigs were assessed for tail damage and skin lesions every 4 wk and during outbreaks of tail biting. Behaviors were video-recorded twice weekly for 13 wk during the growing-finishing period. Carcass weights and incidence of carcass trim loss were recorded. More intact pigs experienced tail damage during both nursery (41% vs. 2%; chi-square = 75.7; P < 0.0001) and growing-finishing (89% vs. 48%; chi-square = 76.2; P < 0.0001) periods than docked pigs. Intact pigs spent more time tail biting (0.31% vs. 0.06%; P < 0.001) and tended to spend less time drinking (1.58 vs. 1.77%; P < 0.10) compared to docked pigs. Intact pigs experienced the first outbreak of tail biting at 11 wk of age, which occurred 6 wk earlier compared to docked pigs. Furthermore, 21% of intact pigs vs. 5% (P < 0.001) of docked pigs were removed due to tail damage. Tail docking did not affect ADG (nursery: 0.48 vs. 0.49 kg, SE = 0.04; growing-finishing: 0.86 vs. 0.87 kg, SE = 0.01 for docked and intact pigs, respectively) or skin lesions of pigs. For pigs that were not removed, ADFI was not different between pens with docked pigs and pens with intact pigs. As a consequence of carcass trim loss, carcass contamination, and mortality, 90% of intact pigs vs. 97% of docked pigs were harvested for full value. These data suggest that raising pigs without tail docking in a confinement housing system increases incidence of tail biting and tail damage, resulting in higher morbidity, reduced value, and compromised welfare of pigs.
Tail biting constitutes a major welfare and health issue in commercial pig rearing, with significant negative economic consequences. Contrary to the aim of the EU directive (2001/93/EC), tail docking is still widely practiced in most EU countries as a measure to reduce the incidence of tail biting and concomitant pathologies. Mutilations are a general welfare concern in all species, and any efforts towards reducing the need for tail docking are important for the future sustainability of the EU pig sector. Sound policy making needs science-based risk assessment, including assessment of the severity of problems and effectiveness of solutions. The general objectives of the FareWellDock-project included estimation of the relative harms associated with tail docking and tail biting, and evaluation of the efficacy of some main preventive measures against tail biting, which could reduce the need for tail docking. The ultimate aim was to stimulate the development towards a non-docking policy in the EU.
The first objective of WP1 was to evaluate measures of acute and chronic pain in relation to tail damage. This included assessment of the short (acute trauma), medium (post trauma inflammation) and long term (traumatic neuroma formation) pain associated with tail docking in neonatal piglets, and the possible consequences for longer term fear of humans. In addition, the studies assessed the effects of tail-damage in more mature pigs to provide a basis for assessing the pain associated with being tail bitten in later life. Finally, studies were conducted to assess the effects of an NSAID analgesic on the short term responses to neonatal tail docking.
Experimental studies confirmed that piglets do experience pain when tail docked, and that pain relief treatment, such as meloxicam, can lessen but not abolish the physiological stress reaction to docking. Piglets which have been tail docked seem more fearful of people afterwards than undocked animals. In docked tails, no difference in pain sensitivity of the tail (as measured by behavioural withdrawal) is detected after 8 weeks, but changes in the functioning of the sensory nerves from the tail can still be measured after 4 months, which suggests that the possibility for longer term pain exists. When the tail is damaged later in life, as happens with tail biting, changes in both tail stump sensitivity and nerve functioning can last for at least 4 months, and possibly beyond.
WP2 focused on the role of manipulable material when reducing the need for tail docking. The aim was to develop and validate ways to assess if on-farm use of manipulable material is sufficient to reduce tail biting. Further, the aim was to describe suitable methods for implementing the use of straw under commercial farming conditions and to investigate, in on-farm conditions, the efficiency of tail docking vs. enrichment given in sufficient quantity to reduce the occurrence of tail lesions.
A screening method to assess the appropriateness of the level of enrichment on-farm was developed and includes scoring of the amount of unsoiled straw, the behaviour, and ear, tail and flank lesions of the pigs. AMI (animal-material interaction) sensors were used e.g. to show that pigs in biter pens were more interested in novel ropes than pigs in control pens, that environmental enrichment may reduce exploratory behaviour of point-source objects, and that sick pigs, experimentally infected with streptococcus spp, were less interested in chain manipulation. The sensors appear to be a promising tool to assess the use of manipulable material by pigs. In countries (SE and FI) where tail docking is not done, farmers report using on average of 30 to 50 g of straw/pig/ day, equivalent to about 0.5 L/pig/day. A survey in SE revealed fewer injurious tail biting outbreaks on farms using larger amounts of straw. Larger amounts of straw were mainly used on farms having scrapers in the slurry channels. A large experimental study showed that a moderate amount of straw (150 gr/pig/day) reduced injurious tail-biting outbreak in finisher pigs by more than 50%, while docking seemed to be more effective as it reduced tail biting by more than four-fold. The effect of both measures was additive, i.e. docking and straw reduced tail biting 9 fold. Further, it was shown that increasing the amount of straw from 10 to up to 400 gr/pig/day had multiple positive effects by progressively reducing the occurrence of tail injuries and stomach ulcers, increasing growth rate, increasing straw-directed behaviour, and reducing redirected behaviours towards other pigs.
In WP3 the aim was to clarify the role of poor health in the causation of tail biting and victimization, and the aim was study early identification of tail-biting outbreaks. In addition, the aim to develop automated systems for early warning of tail biting outbreaks.
The results of experimental and on-farm studies showed that the social behaviour of sick pigs differs from healthy pen mates, as pigs with osteochondrosis received more sniffing and tail bites from their pen mates than healthy pigs, while pigs with mild respiratory disease tended to bite more at the ears and tails of pen mates than healthy pigs did. In addition, studies of cytokines suggest that low-grade inflammation may decrease activity and increase receiving sniffs and attacks from other pigs. Studies on data sets from commercial pig farms indicated that changes in feeding behaviour may be an important sign of an increased risk for tail biting to occur: Future tail bitten individuals showed a reduced feed intake already 2-3 weeks before tail damage became evident. Furthermore, feeding behaviour in groups which develop tail biting may differ from non-biting groups for at least ten weeks prior to an injurious tail-biting outbreak. It was also shown that tail-chewing activity may start 2-3 weeks before tail damage can be seen. A detailed behavioural study of tail biting events revealed that there appears to be no such thing as a ‘typical’ tail-biting event and that the behaviour shown immediately before a tail-biting event does not differ from behaviour prior to another type of social interaction, namely ano-genital sniffing. Thus, it seems difficult to predict if a social event will escalate into tail biting or not. However, tail biting is more likely between pigs that have previously interacted. Data sets from several countries and studies indicated an association between tail-biting damage and tear staining, but the direction of this association is not clear.
In summary the project concluded on a set of practical recommendations, which have been published as part of four factsheets on the FareWellDock-webpage:
Avoid tail docking whenever possible because it definitely causes pain, induces long-term changes in sensory-nerve function and may impair the pigs’ confidence in humans.
Avoid tail biting, and hence the need for tail docking, by addressing risk factors on the farm.
Treat tail-bitten pigs promptly and consider pain relief.
To reduce injurious tail-biting outbreaks, use straw as it might be almost as effective as tail docking. For this purpose, the more straw the better.
To ensure that sufficient straw is allocated check that there is left-over straw before the next day’s allocation.
Keep your pigs healthy. This will be good both for productivity and also help avoid injurious tail-biting outbreaks.
If pigs show signs of illness, be more alert to tail biting risk.
Remove tail-bitten pigs promptly to avoid further damage and treat according to veterinary advice.
Pay special attention to groups of pigs where you see:
high or suddenly increased levels of general activity or exploration
tail manipulation or chewing
swinging or tucked tails
low or decreasing numbers of visits to an automatic feeder or reduced feed intake
Information on project activities and publications have been continuously published on the FareWellDock-webpage. To date, 16 scientific articles have been published, and 9 are in preparation. Communication to stakeholders has been active, both through the FareWellDock-webpage, including 97 blog posts, and by interviews in media in different countries, popular articles and presentations at producer seminars. In October 2016 the results were presented widely at the EU level to policy makers and other stakeholders at the ‘Meeting and Webinar on Actions to Prevent Tail biting and Reduce Tail docking of Pigs’, organized by the European Commission Directorate General for Health and Food Safety in Grange, Ireland.
Due to the positive experience of the cooperation a decision was made at the last project meeting in DK in October 2016 that we will continue our cooperation as the FareWellDock-network, also inviting further researchers and stakeholders to join. The first activity of the FWD-network will be to organise a satellite meeting at the Congress of the International Society for Applied Ethology in August 2017 in DK, and to launch an emailing list to make sure FWD-network members and other researchers keep updated on research progress and related topics.
The FareWellDock factsheets are out. Below you find the cover factsheet as well as the factsheets on tail docking, enrichment, health and the prediction of tail biting. This post shows images of the English versions, and links to the pdf version of the English factsheets, as well as all factsheets in Danish, Dutch, Finnish, French, Italian, Norwegian and Swedish. Separate pages are available directly showing the factsheets in the other languages (Danish, Dutch, Finnish, French, Italian, Norwegian and Swedish).
By M.K. Pierdon, A.M. John and T.D. Parsons. in: Journal of Swine Health and Production 24(6):309-314 · November 2016
More gestating sows are being housed in pens where it is challenging to implement controlled exposure to pathogens for disease control (“feedback”). Ice blocks provide a possible vehicle for feedback material in pen gestation. Ice blocks were placed once weekly for 6 consecutive weeks in a pen of approximately 130 sows to test whether sows would interact with the blocks of ice. Sows were housed in a large, dynamic pre-implantation group fed with electronic sow feeders. Each ice block was video-recorded for 1 hour. All sows that contacted it were identified. The number of sows, their duration of contact, and amount of aggression were coded from the video. Median number of sows that interacted with the ice was 94, and increasing the number of ice blocks from two to four per pen increased the median number of sows to contact the ice and the median duration of an individual sow’s contact with the ice, and decreased the amount of aggression at each block. Our findings suggest ice blocks are a convenient vehicle for controlled exposure of feedback material to gestating sows housed in large pens. However, additional studies are needed to validate pathogen exposure with this method.
Tail docking is applied to young piglets to avoid a potential problem later of tail biting. However, should the root of the problem be looked at instead of using this preemptive measure?
Tail docking is routinely performed on farms as a means to decrease the prevalence of tail biting. Tail biting is an abnormal redirected exploratory behaviour that results in mild to severe injury of pen mate’s tails. Several factors have been associated with tail biting behaviour including environment, nutrition, gender, genetics and health status.
Tail docking of piglets has and continues to be highly criticised in both the US and Europe. This is primarily driven by the fact that tail docking is a painful procedure as indicated by changes to the physiology and behaviour of pigs who are tail docked.
Eliminate tail docking and control tail biting
Most recently, European countries have taken a stance to eliminate this management practice by managing the problems which lead to tail biting in the first place. Several research projects including FareWellDock have been established to provide scientific research to determine the best practices to eliminate tail docking and control tail biting. Although several factors can contribute to tail biting, research has consistently demonstrated that the absence of material for manipulation increases risk of tail biting. Several enrichment objects including chains, rubber hoses, car tires, straw and peat moss have shown to decrease tail biting but not necessarily eliminate the behaviour altogether.
Unlike the European approach, the US is nowhere near implementing the elimination of tail docking on farm. Tail docking is still performed routinely on commercial swine operations in the US. Farms which are not tail docking are either smaller farms which provide outdoor access to pigs or farms on specified animal welfare friendly programmes like Animal Welfare Approved, American Humane and Certified Humane.
For the second part of this article (on the probability of eliminating tail docking and the value of enrichment) see the original at the Pig Progress site (and see also the comment section).
Tail biting is a common problem in growing–finishing pigs, which can compromise health, growth, and welfare of pigs. Because tail biting is an abnormal behavior performed by tail biters toward victimized pigs, understanding these pigs may help us solve the problem. This study was conducted to evaluate immune function of tail biters and victimized pigs. Pigs (n = 240; 25.7 ± 2.9 kg initial weight) were housed in 8 pens of 30 pigs for 16 wk. Once visible blood on a tail appeared, pigs in that pen were assessed daily for tail score (0 = no damage, 1 = healed lesions, 2 = visible blood without swelling, 3 = swelling and signs of infection, and 4 = partial or total loss of the tail). Victimized pigs were defined as pigs with tail scores equal to or greater than 2. Meanwhile, a 2-h observation was conducted for 2 consecutive days to identify tail biters. In each pen in which tail biting occurred, blood samples were collected from victimized pigs on the day that tail biting was first observed as well as from tail biters and 2 control pigs with no sign of tail damage. Fourteen biters (6 barrows and 8 gilts), 30 victimized pigs (21 barrows and 9 gilts), and 28 control pigs (14 barrows and 14 gilts) were identified for blood sampling. Total serum protein and IgG concentrations were analyzed using the spectrophotometric method. Data were analyzed using the Glimmix model of SAS (SAS Inst. Inc., Cary, NC). Compared with control and victimized pigs, tail biters had lower total serum protein (P = 0.01; Table 018) and IgG concentrations (P = 0.01), suggesting poor immunity. There were no differences in total serum protein or IgG concentrations between control and victimized pigs. These preliminary results suggest that tail biters may experience compromised immunity.
Tear staining or chromodacryorrhea refers to a dark stain below the inner corner of the eye, caused by porphyrin-pigmented secretion from the Harderian gland. It has been shown to be a consistent indicator of stress in rats and to correlate with social stress and a barren environment in pigs. The current study was, to our knowledge, the first to test it on commercial pig farms as a potential welfare indicator. The study was carried out on three commercial farms in Finland, in connection to a larger study on the effects of different types of manipulable objects on tail and ear biting and other behavioural parameters. Farm A was a fattening farm, on which 768 growing-finishing pigs were studied in 73 pens. Farm B had a fattening unit, in which 656 growing-finishing pigs were studied in 44 pens, and a farrowing unit, in which 29 sows and their litters totalling 303 piglets were studied in 29 pens. Farm C was a piglet-producing farm, on which 167 breeder gilts were studied in 24 pens. Data collection included individual-level scoring of tear staining; scoring of tail and ear damage in the growing-finishing pigs and breeder gilts; a novel object test for the piglets; and a novel person test for the growing-finishing pigs on Farm B and the breeder gilts on Farm C. On Farm A, tear staining was found to correlate with tail damage scores (n=768, r s =0.14, P<0.001) and ear damage scores (n=768, r s =0.16, P<0.001). In the growing-finishing pigs on Farm B, tear staining of the left eye correlated with tail damage (n=656, r s =0.12, P<0.01) and that of the right eye correlated with ear damage (n=656, r s =0.10, P<0.01). On Farm A, tear-staining sores were lower in the treatment with three different types of manipulable objects as compared with controls (mean scores 3.3 and 3.9, respectively, n=31, F29=4.2, P<0.05). In the suckling piglets on Farm B, tear staining correlated with the latency to approach a novel object (n=29, r p =0.41, P<0.05). Although correlations with tail and ear damage were low, it was concluded that tear staining has promising potential as a new, additional welfare indicator for commercial pig farming. Further research is needed on the mechanisms of tear staining.